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Diagram Software, With 3-D Views, Helps Reconstructionists Build More Accurate Crash Scene Reports
By Bob Galvin

Diagramming software is quickly becoming one of an accident reconstructionist's most valuable tools. Why? Primarily because the software acts as a kind of "crystal ball" in reverse; it allows the reconstructionist to define what people should or might have seen at either a crash or crime scene. This kind of 20/20 hindsight can be crucial and persuasive, especially when a case involving a perplexing crash or crime scene ever goes to court.

Tim Brown, who is both an active police officer and consulting accident investigator in Rochester, New Hampshire, sees numerous benefits from using diagramming software. Key among these include higher accuracy of drawing details, dramatically shortened drawing time, and easy, quick updating of a drawing.
3-D Viewer Shows What Driver May Have Seen

Brown uses a total station system, and one of the diagramming software products he has selected is the Crash Zone and Crime Zone programs with an integrated 3-D Viewer, all from The CAD Zone, Inc., Beaverton, Oregon. He is able to import the crash scene measurements he captures with is total station into The Crash Zone program, then display it in 3-D format. Says Brown: "With the 3-D Viewer, you can look at the diagram from any perspective. If you're doing a car crash, you can lower the viewer to the height of each driver to get a perspective of what each driver should have been able to see."

The same scenario holds true for a shooting situation, adds Brown, who notes that a camera can be placed where the shooter was standing to show what was in the line of fire or what danger certain people faced during the time of that shooting. "You can also reverse it," Brown continues. "If it's a police-involved shooting, you can put the camera in place where the police officer was to show that he was definitely in the line of fire and in a dangerous situation. It's a very powerful presentation tool," Brown said.

Randall L. Tanghe, a police sergeant and accident reconstructionist with the Hilltown Township Police Department in Pennsylvania, says diagramming software has made his already complex job easier. Tanghe uses The CAD Zone's Crash Zone software program with 3-D Viewer. He also uses an LTI Laser Measurement system from Laser Technology to make measurements at a crash scene, then imports them into Crash Zone. "This enables me to diagram collision scenes and geometrically complex intersections to an extremely high degree of exactitude," Tanghe said.

Photo of a crash that killed two young and promising youth ministers
(who were about to announce their engagement) while exiting a church parking lot

the diagram made with Crash Zone

In addition to police and accident reconstructionist duties, Tanghe is also a private consultant to other police agencies, prosecuting attorneys and insurance companies in cases involving serious injury and wrongful death litigation, and the prosecution of vehicular suicide cases. Tanghe also teaches forensic mapping and diagramming software classes.

For both Tanghe and Brown, getting at the truth of what really happened at a crash scene is at the core of their jobs. And without the aid of precise software such as the Crash Zone, this truth might be overshadowed by speculation. Hand-drawn diagrams can be inaccurate, according to Tanghe. "Whenever you have intersections with complex geometry, your accuracy and precision in measuring is questionable at best," Tanghe said. "Then, after taking the measurements by hand you must draw it. With out using a CAD-based drawing system, you have yet another area for potential inaccuracy."

Brown adds that off-the-shelf CAD software programs can be limiting. "This is because you're trying to adapt an engineering based software to perform a function in law enforcement," he said. Beyond this hurdle, Brown cites a long learning curve and high pricing as added deficits to using software that doesn't target law enforcement professionals.

Diagrams Powerful in Court
Why this is so important is evident when vehicular crash cases head to court. A jury can make a more informed judgment on a case when presented with clear and detailed diagrams, especially when the diagrams are in a 3-D view. According to Brown, the diagram of a crash scene, which is usually blown up for full view by a jury and attorneys, is a helpful aid. "The software preserves a scene so both sides can see it equally from their own perspective," Brown said. "The three-dimensional representation is phenomenal because it's like looking through the eyes of a driver."

For Randy Tanghe, it's not uncommon for him to appear in court 15 to 20 times a year to present reconstructions of vehicular homicide cases. When he presents diagrams, they usually are layered so that he can show a simplistic view of vehicles at final rest, then progressive view showing cars at impact, and ultimately a layer with angular and linear dimensions tied to approach and departure angles.

"I'll try to find the truth at each crash," Tanghe says. "There are occasions where a person is exonerated as a direct result of my reconstruction. Many times we prosecute as a result, too." Regardless of the outcome, the Crash Zone software is instrumental in building Tanghe's definitive diagrammed presentation.

The photo is an overhead view of a single vehicle that crashed into a utility pole. Sellersville [below] shows the diagram made with Crash Zone. The driver in this case lost control of his car while driving around a curve. The car hit the utility pole on the driver's side, seriously injuring both the driver and the passenger.

The diagram made with Crash Zone

Both Brown and Tanghe cite the comprehensive symbols library that accompanies Crash Zone as a valuable feature when diagramming reconstructed accident scenes. There is a symbol for nearly any application that a reconstructionist might need. The method of placing symbols is extremely flexible, which saves time on every drawing. "The Crash Zone allows me to change a symbol's color, rotation, and size all in one step as I place it in the drawing," Brown says. "Many other programs require you to make each of these changes with a separate command, which really slows down the drawing process."

The ability to pose a body is also critical. For example, notes Tanghe, "if you have a struck pedestrian and the body has been all contorted as a direct result of the collision forces, the Crash Zone lets you replicate the position of a body exactly and with anatomical precision."

Brown likes the fact that Crash Zone allows him to create roadways to scale. "If you're taking 220 to 250 measurements at a scene, you'd be out there all day," Brown said. "Now, with the total station and Crash Zone, this has been knocked down to a couple of hours."

The CAD Zone

By Bob Galvin of Galvin and Associates

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